Use canonical underlying type reference

compiler/src/dotty/tools/dotc/transform/ReifyQuotes.scala

@@ -77,7 +77,6 @@ class ReifyQuotes extends MacroTransform {
       case tree: RefTree if !Inliner.inInlineMethod =>
         assert(!tree.symbol.isQuote)
         assert(!tree.symbol.isExprSplice)
-        assert(!tree.symbol.isTypeSplice)
       case _ : TypeDef =>
         assert(!tree.symbol.hasAnnotation(defn.InternalQuoted_QuoteTypeTagAnnot),
           s"${tree.symbol} should have been removed by PickledQuotes because it has a @quoteTypeTag")
@@ -210,16 +209,15 @@ class ReifyQuotes extends MacroTransform {
      *  are in the body of an inline method.
      */
      protected def transformSpliceType(body: Tree, splice: Select)(using Context): Tree =
-      if (level > 1) {
+      if level > 1 then
         val body1 = nested(isQuote = false).transform(body)(using spliceContext)
         cpy.Select(splice)(body1, splice.name)
-      }
-      else {
-        assert(level == 1, "unexpected top splice outside quote")
+      else if level == 1 then
         val (body1, quotes) = nested(isQuote = false).splitSplice(body)(using spliceContext)
         val tpe = outer.embedded.getHoleType(body, splice)
         makeHole(splice.isTerm, body1, quotes, tpe).withSpan(splice.span)
-      }
+      else
+        splice
 
     /** Transforms the contents of a nested splice
      *  Assuming

tests/neg-macros/i6997.scala

@@ -2,7 +2,7 @@
 import scala.quoted._
 class Foo {
   def mcrImpl(body: Expr[Any])(using t: Type[_ <: Any])(using ctx: QuoteContext): Expr[Any] = '{
-    val tmp = ???.asInstanceOf[$t] // error // error
+    val tmp = ???.asInstanceOf[t.Underlying] // error // error
     tmp
   }
 }

tests/neg-macros/i7048e.scala

@@ -16,18 +16,18 @@ abstract class Test {
       import t.given
       println(summon[Type[t.T]].show)
       // val r = '{Option.empty[t.T]} // access to value t from wrong staging level
-      val r2 = '{Option.empty[${t.T}]} // works
+      val r2 = '{Option.empty[t.T.Underlying]} // works
     }
 
     {
-      val r1 = '{Option.empty[${T}]} // works
-      val r2 = '{Option.empty[List[${T}]]} // works
-      val r3 = '{summon[Type[${T}]]} // error: is not stable
-      val r4 = '{summon[${T} <:< Any]} // error: is not stable
+      val r1 = '{Option.empty[T.Underlying]} // works
+      val r2 = '{Option.empty[List[T.Underlying]]} // works
+      val r3 = '{summon[Type[T.Underlying]]} // error: is not stable
+      val r4 = '{summon[T.Underlying <:< Any]} // error: is not stable
     }
 
     {
-      val s = '{Option.empty[${T}]} // works
+      val s = '{Option.empty[T.Underlying]} // works
       val r = '{identity($s)} // works
       val r2 = '{identity(${s: Expr[Option[T]]})} // error // error : is not stable
     }

tests/pos-macros/i4023c/Macro_1.scala

@@ -1,5 +1,5 @@
 import scala.quoted._
 object Macro {
   inline def ff[T](x: T): T = ${ impl('x) }
-  def impl[T](x: Expr[T])(implicit t: Type[T], qctx: QuoteContext): Expr[T] = '{ $x: $t }
+  def impl[T](x: Expr[T])(implicit t: Type[T], qctx: QuoteContext): Expr[T] = '{ $x: T }
 }

tests/pos-macros/i4774a.scala

@@ -3,7 +3,7 @@ import scala.quoted._
 
 object Test {
   def loop[T](x: Expr[T])(implicit t: Type[T], qctx: QuoteContext): Expr[T] = '{
-    val y: $t = $x
+    val y: T = $x
     ${loop('y)}
   }
 }

tests/neg-macros/i4774b.scala → tests/pos-macros/i4774b.scala

@@ -3,8 +3,8 @@ import scala.quoted._
 
 object Test {
   def loop[T](x: Expr[T])(implicit t: Type[T], qctx: QuoteContext): Expr[T] = '{
-    val y: $t = $x;
-    ${loop[$t]( // error
+    val y: t.Underlying = $x;
+    ${loop[t.Underlying](
       'y
     )}
   }

tests/pos-macros/i6210/Macros_1.scala

@@ -7,8 +7,8 @@ object Macro {
   def impl[A : Type, B : Type](using QuoteContext): Expr[Any] = {
     val t = Type[Map[A, B]]
     '{
-      new Object().asInstanceOf[$t]
-      ???.asInstanceOf[$t]
+      new Object().asInstanceOf[t.Underlying]
+      ???.asInstanceOf[t.Underlying]
     }
   }
 }

tests/pos-macros/i7048e.scala

@@ -16,18 +16,18 @@ abstract class Test {
       import t.given
       println(summon[Type[t.T]].show)
       // val r = '{Option.empty[t.T]} // access to value t from wrong staging level
-      val r2 = '{Option.empty[${t.T}]}
+      val r2 = '{Option.empty[t.T.Underlying]}
     }
 
     {
-      val r1 = '{Option.empty[${T}]} // works
-      val r2 = '{Option.empty[List[${T}]]} // works
-      // val r3 = '{summon[Type[${T}]]} // access to Test.this from wrong staging level
-      val r4 = '{summon[${T} <:< Any]}
+      val r1 = '{Option.empty[T.Underlying]} // works
+      val r2 = '{Option.empty[List[T.Underlying]]} // works
+      // val r3 = '{summon[Type[T.Underlying]]} // access to Test.this from wrong staging level
+      val r4 = '{summon[T.Underlying <:< Any]}
     }
 
     {
-      val s = '{Option.empty[${T}]}
+      val s = '{Option.empty[T.Underlying]}
       val r = '{identity($s)} // works
       val r2 = '{identity(${s: Expr[Option[T]]})}
     }

tests/pos-macros/i7405.scala

@@ -6,7 +6,7 @@ class Foo {
       val x: X = ???
       ${
         val t: Type[X] = Type[X] // Level 0
-        '{ val y: $t = x }
+        '{ val y: t.Underlying = x }
       }
     }
   }

tests/pos-macros/i7405b.scala

@@ -11,7 +11,8 @@ class Foo {
       type Z = x.Y
       ${
         val t: Type[Z] = Type[Z]
-        '{ val y: $t = x.y }
+        '{ val y: Z = x.y }
+        '{ val y: t.Underlying = x.y }
       }
     }
   }

tests/pos-macros/i7887.scala

@@ -1,7 +1,7 @@
 def typed[A](using t: quoted.Type[A], qctx: quoted.QuoteContext): Unit = {
   import qctx.reflect._
   '{
-    type T = $t
+    type T = A
     ${'{???}.cast[T]}
   }
 }

tests/pos-macros/i9020-b/Macro_1.scala

@@ -8,8 +8,8 @@ object Show {
   import quoted._
   def impl[T](using ctx: QuoteContext, tpe: Type[T]): Expr[Show[T]] =
     '{
-      new Show[$tpe] {
-        def show(t: $tpe): String = "TODO"
+      new Show[tpe.Underlying] {
+        def show(t: tpe.Underlying): String = "TODO"
       }
     }
 }

tests/pos-macros/quote-1.scala

@@ -3,7 +3,7 @@ import scala.quoted._
 class Test(using QuoteContext) {
 
   def f[T](x: Expr[T])(implicit t: Type[T]) = '{
-    val y: $t = $x
+    val y: T = $x
     val z = $x
   }
 

tests/run-macros/i7887/Macro_1.scala

@@ -3,7 +3,7 @@ def myMacroImpl(a: quoted.Expr[_])(using qctx: quoted.QuoteContext) = {
   def typed[A] = {
     implicit val t: quoted.Type[A] = a.unseal.tpe.widen.seal.asInstanceOf[quoted.Type[A]]
     '{
-      type T = $t
+      type T = A
       ${a.unseal.seal.cast[T]}
     }
   }

tests/run-macros/refined-selectable-macro/Macro_2.scala

@@ -14,10 +14,10 @@ object Macro2 {
   object Record extends SelectableRecordCompanion[Record] {
     import scala.quoted._
 
-    inline def apply[R <: Record](elems: (String, Any)*) : R = ${ applyImpl('elems, Type[R]) }
+    inline def apply[R <: Record](elems: (String, Any)*) : R = ${ applyImpl[R]('elems) }
 
-    def applyImpl[R <: Record: Type](elems: Expr[Seq[(String, Any)]], ev: Type[R])(using qctx: QuoteContext) = {
-      '{ new Record($elems:_*).asInstanceOf[$ev] }
+    def applyImpl[R <: Record: Type](elems: Expr[Seq[(String, Any)]])(using qctx: QuoteContext) = {
+      '{ new Record($elems:_*).asInstanceOf[R] }
     }
 
     def fromUntypedTuple(elems: (String, Any)*): Record = Record(elems: _*)

tests/run-staging/i3823-b.scala

@@ -4,7 +4,7 @@ object Test {
   given Toolbox = Toolbox.make(getClass.getClassLoader)
   def main(args: Array[String]): Unit = withQuoteContext {
     def f[T](x: Expr[T])(implicit t: Type[T]) = '{
-      val z: $t = $x
+      val z: t.Underlying = $x
     }
     println(f('{2})(Type[Int]).show)
   }

tests/run-staging/i3823.scala

@@ -3,9 +3,9 @@ import scala.quoted.staging._
 object Test {
   given Toolbox = Toolbox.make(getClass.getClassLoader)
   def main(args: Array[String]): Unit = withQuoteContext {
-    def f[T: Type](x: Expr[T])(t: Type[T]) = '{
-      val z: $t = $x
+    def f[T](x: Expr[T])(using t: Type[T]) = '{
+      val z: t.Underlying = $x
     }
-    println(f('{2})(Type[Int]).show)
+    println(f('{2})(using Type[Int]).show)
   }
 }

tests/run-staging/i3847-b.scala

@@ -6,7 +6,7 @@ object Arrays {
   implicit def ArrayIsLiftable[T: Liftable](implicit t: Type[T], qctx: QuoteContext): Liftable[Array[List[T]]] = {
     new Liftable[Array[List[T]]] {
       def toExpr(arr: Array[List[T]]) = '{
-        new Array[List[$t]](${Expr(arr.length)})
+        new Array[List[T]](${Expr(arr.length)})
         // TODO add elements
       }
     }

tests/run-staging/i3847.scala

@@ -6,7 +6,7 @@ object Arrays {
   implicit def ArrayIsLiftable[T: Liftable](implicit t: Type[T], ct: Expr[ClassTag[T]]): Liftable[Array[T]] = {
     new Liftable[Array[T]] {
       def toExpr(arr: Array[T]) = '{
-        new Array[$t](${Expr(arr.length)})($ct)
+        new Array[t.Underlying](${Expr(arr.length)})($ct)
         // TODO add elements
       }
     }

tests/run-staging/i4044e.scala

@@ -7,7 +7,7 @@ class Foo {
     val e: Expr[Int] = '{3}
     val f: Expr[Int] = '{5}
     val t: Type[Int] = Type[Int]
-    val q = '{ ${ '{ ($e + $f).asInstanceOf[$t] } } }
+    val q = '{ ${ '{ ($e + $f).asInstanceOf[t.Underlying] } } }
     println(q.show)
   }
 }

tests/run-staging/i5247.scala

@@ -9,10 +9,10 @@ object Test {
   }
   def foo[H : Type](using QuoteContext): Expr[H] = {
     val t = Type[H]
-    '{ null.asInstanceOf[$t] }
+    '{ null.asInstanceOf[t.Underlying] }
   }
   def bar[H : Type](using QuoteContext): Expr[List[H]] = {
     val t = Type[List[H]]
-    '{ null.asInstanceOf[$t] }
+    '{ null.asInstanceOf[t.Underlying] }
   }
 }

tests/run-staging/quote-lib.scala

@@ -127,12 +127,12 @@ package liftable {
   }
 
   object Lets {
-    def letVal[T, U: Type](expr: Expr[T])(body: Expr[T] => Expr[U])(implicit t: Type[T], qctx: QuoteContext): Expr[U] =
-      '{ val letVal: $t = $expr; ${ body('letVal) } }
-    def letLazyVal[T, U: Type](expr: Expr[T])(body: Expr[T] => Expr[U])(implicit t: Type[T], qctx: QuoteContext): Expr[U] =
-      '{ lazy val letLazyVal: $t = $expr; ${ body('letLazyVal) } }
-    def letDef[T, U: Type](expr: Expr[T])(body: Expr[T] => Expr[U])(implicit t: Type[T], qctx: QuoteContext): Expr[U] =
-      '{ def letDef: $t = $expr; ${ body('letDef) } }
+    def letVal[T: Type, U: Type](expr: Expr[T])(body: Expr[T] => Expr[U])(implicit qctx: QuoteContext): Expr[U] =
+      '{ val letVal: T = $expr; ${ body('letVal) } }
+    def letLazyVal[T: Type, U: Type](expr: Expr[T])(body: Expr[T] => Expr[U])(implicit qctx: QuoteContext): Expr[U] =
+      '{ lazy val letLazyVal: T = $expr; ${ body('letLazyVal) } }
+    def letDef[T: Type, U: Type](expr: Expr[T])(body: Expr[T] => Expr[U])(implicit qctx: QuoteContext): Expr[U] =
+      '{ def letDef: T = $expr; ${ body('letDef) } }
   }
 
   object Loops {
@@ -145,7 +145,7 @@ package liftable {
 
     implicit class LiftedOps[T: Liftable](list: Expr[List[T]])(implicit t: Type[T]) {
       def foldLeft[U](acc: Expr[U])(f: Expr[(U, T) => U])(implicit u: Type[U], qctx: QuoteContext): Expr[U] =
-        '{ ($list).foldLeft[$u]($acc)($f) }
+        '{ ($list).foldLeft[U]($acc)($f) }
       def foreach(f: Expr[T => Unit])(using QuoteContext): Expr[Unit] =
         '{ ($list).foreach($f) }
     }

tests/run-staging/quote-owners-2.scala

@@ -12,8 +12,8 @@ object Test {
 
   def f(t: Type[List[Int]])(using QuoteContext): Expr[Int] = '{
     def ff: Int = {
-      val a: $t = {
-        type T = $t
+      val a: t.Underlying = {
+        type T = t.Underlying
         val b: T = 3 :: Nil
         b
       }

tests/run-staging/quote-type-tags.scala

@@ -5,7 +5,7 @@ object Test {
   given Toolbox = Toolbox.make(getClass.getClassLoader)
   def main(args: Array[String]): Unit = run {
     def asof[T: Type, U](x: Expr[T], t: Type[U]): Expr[U] =
-      '{$x.asInstanceOf[$t]}
+      '{$x.asInstanceOf[t.Underlying]}
 
     println(asof('{}, Type[Unit]).show)
     println(asof('{true}, Type[Boolean]).show)

tests/run-staging/quote-unrolled-foreach.scala

@@ -57,7 +57,7 @@ object Test {
     val size = ($arrRef).length
     var i = 0
     while (i < size) {
-      val element: $t = ($arrRef)(i)
+      val element: T = ($arrRef)(i)
       ($f)(element)
       i += 1
     }